<script lang="ts">
    import { Empty } from "@gradio/atoms";
    import { BlockLabel } from "@gradio/atoms";
    import { Music } from "@gradio/icons";
    import type { I18nFormatter } from "@gradio/utils";
    import { createEventDispatcher } from "svelte";
    import { onMount } from "svelte";

    import { start, stop } from "./webrtc_utils";
    import AudioWave from "./AudioWave.svelte";

    export let value: string | null = null;
    export let label: string | undefined = undefined;
    export let show_label = true;
    export let rtc_configuration: Object | null = null;
    export let i18n: I18nFormatter;
    export let on_change_cb: (msg: "change" | "tick") => void;
    export let icon: string | undefined = undefined;
    export let icon_button_color: string = "var(--color-accent)";
    export let pulse_color: string = "var(--color-accent)";
    export let icon_radius: number = 50;

    export let server: {
        offer: (body: any) => Promise<any>;
    };

    let stream_state: "open" | "closed" | "waiting" = "closed";
    let audio_player: HTMLAudioElement;
    let pc: RTCPeerConnection;
    let _webrtc_id = Math.random().toString(36).substring(2);

    const dispatch = createEventDispatcher<{
        tick: undefined;
        error: string;
        play: undefined;
        stop: undefined;
    }>();

    onMount(() => {
        window.setInterval(() => {
            if (stream_state == "open") {
                dispatch("tick");
            }
        }, 1000);
    });

    async function start_stream(value: string): Promise<string> {
        if (value === "start_webrtc_stream") {
            stream_state = "waiting";
            _webrtc_id = Math.random().toString(36).substring(2);
            value = _webrtc_id;
            pc = new RTCPeerConnection(rtc_configuration);
            pc.addEventListener("connectionstatechange", async (event) => {
                switch (pc.connectionState) {
                    case "connected":
                        console.info("connected");
                        stream_state = "open";
                        break;
                    case "disconnected":
                        console.info("closed");
                        stop(pc);
                        break;
                    case "failed":
                        stream_state = "closed";
                        dispatch("error", "Connection failed!");
                        stop(pc);
                        break;
                    default:
                        break;
                }
            });
            let stream = null;
            const timeoutId = setTimeout(() => {
                // @ts-ignore
                on_change_cb({ type: "connection_timeout" });
            }, 5000);

            start(
                stream,
                pc,
                audio_player,
                server.offer,
                _webrtc_id,
                "audio",
                on_change_cb,
            )
                .then((connection) => {
                    clearTimeout(timeoutId);
                    pc = connection;
                })
                .catch(() => {
                    clearTimeout(timeoutId);
                    console.info("catching");
                    dispatch(
                        "error",
                        "Too many concurrent users. Come back later!",
                    );
                });
        }
        return value;
    }

    $: start_stream(value).then((val) => {
        value = val;
    });
</script>

<BlockLabel
    {show_label}
    Icon={Music}
    float={false}
    label={label || i18n("audio.audio")}
/>
<audio
    class="standard-player"
    class:hidden={true}
    on:load
    bind:this={audio_player}
    on:ended={() => dispatch("stop")}
    on:play={() => dispatch("play")}
/>
{#if value !== "__webrtc_value__"}
    <div class="audio-container">
        <AudioWave
            audio_source_callback={() => audio_player.srcObject}
            {stream_state}
            {icon}
            {icon_button_color}
            {pulse_color}
            {icon_radius}
        />
    </div>
{/if}
{#if value === "__webrtc_value__"}
    <Empty size="small">
        <Music />
    </Empty>
{/if}

<style>
    .audio-container {
        display: flex;
        height: 100%;
        flex-direction: column;
        justify-content: center;
        align-items: center;
    }

    .standard-player {
        width: 100%;
    }

    .hidden {
        display: none;
    }
</style>
